Industrial paints and coatings must satisfy a number of competing requirements. For example, the hardened or cured coating may require a glossy appearance, solvent resistance, or resistance to detergents or other alkaline treatments. Some previously-employed coating systems have become unacceptable for environmental reasons, such as their excessive emissions of solvents now classified as volatile hazardous air pollutants (VHAPs) or volatile organic compounds (VOCs). Coatings applied to plastics may need to be dried or cured in an oven so that the coated parts can be quickly processed and shipped or stored. The dried or cured coating may also require good blocking resistance, especially when freshly-coated parts must be stacked together, or when coated parts must be shipped in conditions (e.g., inside tractor trailers) which may expose the coated parts to elevated temperatures. For some applications such as plastic molding manufacture, coated plastic parts or stock are deliberately bent or otherwise deformed (sometimes with the assistance of heat) in a subsequent manufacturing step. In such instances the coating should remain sufficiently well-adhered to the plastic substrate so that the coating preserves its functional and appearance features after the deformation step.
Wood-frame windows and other wooden architectural elements that will be exposed to outdoor conditions are often protected by the manufacturer by dipping or otherwise treating the wood with a preservative containing wax, mildewcide and other ingredients. The thus-coated pieces are dried and then topcoated with a clear or sometimes pigmented stain or paint. The wax in the preservative can make it difficult for the topcoat to adhere well to the treated wood substrate.
From the foregoing, it will be appreciated that what is needed in the art are coating compositions that will adhere well to hard plastics and to wood treated with wax-containing preservatives. Such compositions and methods for their use are disclosed and claimed herein.